Tutorial: RF Mixers: Analysis and Design Trade-offs

Mixers are essential building blocks of every RF transceiver, often compromising the noise and linearity performance of the entire receive or transmit chain. Specifically, the switching action involved in mixing typically dictates the choice of the radio architecture and proper frequency planning to avoid the receiver desensitization. In this tutorial various mixer architectures such as passive and active, current-mode and voltage-mode, and their properties are analyzed and discussed. Of special importance is the noise response of mixers, which is not very well understood due to the nonlinear and time varying nature of the block, and the fact that conventional linear noise analysis applicable to amplifiers often does not hold. We will focus on intuitive and qualitative ways of analyzing the noise of both passive and active mixers as well.